1. Technical Field
This invention relates generally to surgical apparatus, and more particularly to sterile protective apparatus used to cover imaging heads of radiological imaging equipment.
2. Related Art
The need to provide a sterile environment in a surgical theatre is directly associated with the known risk of infection that can be caused by bacteria, such as from a person or surgical equipment, in the surgical theatre. As such, it is known that in order to minimize the risk of infection during a surgical procedure, it is necessary to prevent the transfer of bacteria, such as via airborne lint or dust particles, fluids, or otherwise, within the surgical theatre. Although the risks of infection caused during surgery are known, it remains a challenge to minimize the risks associated with the onset of infection caused during surgery. Infections have been estimated to affect about 2 million patients annually and result, directly or indirectly, in an estimated 100,000 deaths. Aside from the loss of life, infections create an economic burden on hospitals. For example, some studies estimate that each bloodstream infection in a patient results in an average cost of about $27,000 to the hospital. As such, many states have passed laws detailing how hospitals treat patients in an effort to decrease the risk of infection to the patients.
In orthopedic surgeries it is common to take radiological images of various parts of the patient's body as the surgery is being performed. One common piece of radiological imaging equipment used to image the patient is a fluoroscopy system including a fluoroscope. The fluoroscopy system allows the physician to obtain real-time moving images of the internal structures of a patient through the use of the fluoroscope. In its simplest form, a fluoroscope consists of an X-ray emitter and fluorescent screen, between which, a portion of a patient is placed. Modern fluoroscopes couple the fluorescent screen to an X-ray intensifier or detector and a CCD video camera allowing the images to be recorded and played real-time on a monitor.
One common fluoroscopy system used to image the patient is a C-arm fluoroscopy unit. A C-arm fluoroscopy unit obtains its name from a C-shaped arm extending between opposite ends, with one end having an X-ray emitting head attached thereto and the opposite end having a X-ray imaging head attached thereto. Different types of X-ray imaging heads commonly used are known as flat detectors and image intensifiers. Regardless of the type of imaging head used, they typically have an outer flat imaging surface.
During some procedures, the physician may place a patient's limb directly on the flat imaging surface to facilitate performing the surgical procedure. This is particularly common in orthopedic procedures, such as on a hand or arm, for example. During these procedures, the physician needs to see, in real-time, the location of surgical instruments, such as Kirschner wires, commonly referred to as “K-wires”, which are sterilized, sharpened, smooth stainless steel pins. K-wires come in different sizes and are used to hold bone fragments together (pin fixation) or to provide an anchor for skeletal traction. The pins are often driven into the bone through the skin (percutaneous pin fixation) using a power or hand drill. As such, when the patient's limb is positioned directly on the flat imaging surface, it is important for the physician to be extremely careful when positioning the K-wire to avoid causing damage to the underlying imaging surface, such as can occur if the K-wire is inadvertently driven through the patient's skin. Given the fact that, in many cases, the physician is using a good deal of force to position the K-wire, it is not unheard of for the K-wire to extend through the patient's skin and impinge the underlying image surface, thereby causing damage to the imaging surface, regardless of how much care the physician is using.
In addition to being careful to avoid damaging the imaging surface, it is particularly important to ensure the flat surface is sterile. Further yet, the flat imaging surface must remain uniformly radiolucent, which is a problem when using common protective apparatus in the form of bag-shaped sterile drapes to cover the flat, non-sterile imaging surface of the imaging head. When using a bag-shaped sterile drape, the drape is typically placed over the flat imaging surface to provide a sterile barrier about the imaging surface. Unfortunately, wrinkles typically form in the highly flexible sterile drape over the flat imaging surface, which in turn causes the resulting image produced by the imaging head to be distorted. As such, the surgeon, whom is reliant on the images produced by the imaging equipment to perform the surgery, is forced to work with less than clear images, thereby complicating the surgery process.